1. Field of the Invention
The present invention is directed generally to systems and methods of construction, and more specifically, to systems and methods for adhering and sealing joints between adjoining materials.
2. Description of the Related Art
In the construction of homes, building, or other structures, it is common to use sealants or caulk to adhere one or more joints together. The term “caulk” is often referred to as one of the common chemical sealants made from silicone, polyurethane, polysulfide, or acrylic. Other types of chemical sealants are also used in construction to seal joints between adjoining materials.
Different caulks can be used based on the adjoining materials of the joints being sealed. For example, construction caulk is often heavier and used in building construction where no movement is expected. Various caulks are used in joints where movement is expected or other environmental factors need to be considered. Examples of such environmental factors include precipitation, dry climates, or extreme hot and cold temperatures.
Caulks and sealants are generally provided in tubes having a narrow nozzle at one end. A caulking gun is used to apply the caulk or sealant in the joint between two materials. Once applied, there is a curing time for the sealant to properly fill and secure the joint.
While a variety of caulks have been developed that provide specific advantages for various substrate types and environments, it is still common to experience failure over time. Adhesive failure between the caulk and the substrates can occur for a variety of reasons. The most common reasons are substrate movement, caulk shrinkage, improper application on a damp surface, and improper application during non-optimal environmental conditions.
Some systems provide a solution for limiting the problems of adhesive failure through use of a backer rod placed in the joint between two substrates. The backer rod operates to limit the amount of caulk or sealant required, thereby reducing the stress on the caulk-to-substrate bond. However, this approach merely reduces the stress and will eventually fail by one or more of the other conditions described above.
FIG. 1 is an elevational sectional view of a poor caulk joint 104 comprising caulk 105 between two substrates 100 and 110. Excessive thickness of the caulk 105 makes it difficult to stretch, leading to failure of the bond between the caulk and substrates 100 and 110. Common types of sealant and caulk failure are adhesive failure or cohesive failure due to chemical degradation. Adhesive failure is caused by one of: movement between the substrates, caulk shrinkage, improper application, or improper environment.
FIG. 2 is an elevational sectional view of a caulk joint 204 comprising caulk 205 and a backer rod 207 disposed between two adjacent substrates 200 and 210. To limit the amount of caulk 205 required to seal the joint 204, the backer rod 207 is used. In general, the use of the backer rod 207 reduces the thickness of the joint 204 so that the caulk 205 stretches easier and less caulk is required to fill the joint. The use of the backer rod 207 also minimizes bonding stress between the caulk 205 and the substrates 200 and 210.
FIGS. 3A-3D illustrate various types of fractures that can occur between two substrates that are adhered to each other using caulk. Specifically, FIG. 3A is sectional view of a top substrate 300 and a bottom substrate 310 that are adhered to each other using caulk 301. As illustrated, a cohesive fracture 312 occurs within the caulk 301 but does not directly affect the interfaces of the two substrates 300 and 310. FIG. 3B is a sectional view of an adhesive or “interfacial” fracture 314 between the substrates 300 and 310. As illustrated, adhesive fractures in the caulk 301 occur along one or more interfaces (e.g., interface 302 of the substrate 310) of the substrates 300 and 310. Adhesive fractures are also known as interfacial fractures. FIG. 3C is a sectional view of a fracture 316 in the caulk 301 that “jumps” between the adhered substrates 300 and 310. As illustrated, fracture jumping occurs in the caulk 301 by retracting from the interfaces of both of the substrates 300 and 310. FIG. 3D is a sectional view of a fracture 318 in the substrate 300. As illustrated, the fracture 318 in the substrate 300 causes a fracture 320 in the caulk 301 and the interface of the substrate 300. Fractures and degradation in caulk and sealants are not limited to those illustrated in FIGS. 3A-3D. Environmental conditions and improper application can lead to various types of separation from substrate interfaces.